Digestive System (Ch 26) Flashcards
What is the function of the digestive system?
to take in food, break it down, absorb nutrients, and eliminate wastes
What are the two components of the digestive system?
- Alimentary Canal (GI Tract)
2. Accessory Organs
Peritoneum
- ->lining of the abdominopelvic cavity
1. parietal peritoneum: lines body walls
2. visceral peritoneum: lines organs
3. peritoneal cavity: between parietal and visceral, filled with fluid –> prevents friction
Intraperitoneal
inside peritoneal cavity, highly mobile (ex. stomach, liver, ileum, jejunum, tranverse/sigmoid colon)
Retroperitoneal
behind peritoneal cavity, adhered to back wall of abdominopelvic wall (ex. pancreas, duodenum, ascending/descending colon, rectum)
What are the six digestive processes?
- Ingestion
- Mechanical Digestion
- Propulsion
- Chemical Digestion
- Absorption
- Defecation
Celiac Trunk
branch of abdominal aorta, inferior to diagram (along w/superior and inferior mesenteric arteries) Three branches off trunk: 1. Splenic Artery 2. Common Hepatic Artery 3. Gastric Artery
Splenic Artery
supplies blood to spleen
Common Hepatic Artery
supplies blood to the liver
Gastric Artery
supplies blood to the stomach
Superior Mesenteric Artery
supplies small intestine + proximal colon
Inferior Mesenteric Artery
supplies distal colon
Renal Arteries
supplies kidneys
Gonadal Arteries
testicular/ovarian arteries
-branch off high on abdominal aorta and travel inferior to gonads
Hepatic Portal System
series of vessels that drain the GI tract and shunts blood to liver for absorption/processing
Inferior Mesenteric Vein
drains into splenic vein
Superior Mesenteric Vein
connects with splenic vein to form Hepatic Portal Vein
Hepatic Portal Vein
carries blood TO the liver for detox/nutrient processing
Hepatic Veins
how blood EXITS the liver
-feeds into the inferior vena cava
Accessory Organs
Teeth Palates Tongue Salivary Glands Liver Pancreas Gall Bladder
Teeth
–> mechanical digestion (chew food)
*2123
2-incisors
1-canine
2-premolars
3-molars
crown of tooth
exposed part
root of tooth
part in socket
enamel of tooth
- hardest substance in body
- on outside of tooth
dentin of tooth
underneath enamel
Pulp cavity of tooth
filled with loose CT (pulp)
contains vessels and nerves
part of the pulp cavity in root is root canal.
apical foramen of tooth
opening at tip
cementum of tooth
External surface to help hold tooth in place
Periodontal ligament of tooth
anchors tooth in jaw socket
gingiva
gum
salivary glands
secrete enzymes to begin chemical digestion
- parotid: near ear
- submandibular: under mandible
- sublingual: under tongue
Tongue
extrinsic muscle
intrinsic muscle
papillae (fungiform, lingum tonsil)
extrinsic muscle of tongue
attach tongue to skull
intrinsic muscle of tongue
change shape of tongue to help form bolus
papillae
bumps on tongue (not tastebuds)
- filliform: help manipulate food
- lingual tonsil: help prevent infection
Liver
- 2nd largest organ in body
- digestive function –> produce bile to emulsify fats
- processes/converts nutrients
- collects/stores glucose
- detoxifies many poisons/drugs
- makes blood proteins (globulins)
Gallbladder
concentrates/stores bile secreted by liver
empties duodenum by way of common bile duct
Pancreas
*both an exocrine/endocrine gland
- exocrine ducts empty into duodenum
- releases enzymes for protein digestion
- releases sodium bicarbonate to neutralize chyme
- secretes hormones
Hard/Soft Palate
hard: roof of oral cavity, formed from fusion of ventral skull bones
soft: fleshy part of palate composed to muscle + uvula hangs down
Organs of the GI Tract (alimentary canal)
- Pharynx
- Esophagus
- Stomach
- Intestines
- Anus
Pharynx
- swallowing –> voluntary
- pushes bolus from mouth to esophagus
Esophagus
transports bolus from pharynx to stomach
Stomach
- widest part of GI tract
- lined with simple columnar epithelium
- NOT essential for digestion, mostly for storage
- output is chyme to small intestine
What happens in the intestines?
- **digestion/absorption
- fatty acids/fat soluble vitamins diffuse into lipids via lymphatic capillary
- organic materials absorbed directly into bloodstream
Small Intestine
3 regions: duodenum, jejunum, ileum
What does the duodenum receive?
chyme (from stomach)
digestive enzymes (from pancreas)
bile (from liver)
What is the ileocecal valve?
between ileum and cecum
Large Intestine
Primarily for absorption –> water and electrolytes
- appendix: immune function, holds good bacteria
- rectum: holds feces
- anal canal: last subdivision
What are the two sphincters of the anus?
internal anal sphincter: smooth muscle, involuntary –> expels feces
external anal sphincter: skeletal muscle, voluntary –> controls defecation
Haustra
bunched up pouches of intestine
Teniae Coli
longitudinal bands of smooth muscle on superficial colon/cecum
fundus
dome-shaped region lateral and superior to the esophageal connection with the stomach
pyloric sphincter
thick ring of circular smooth muscle that regulates the entrance of chyme into the small intestine
cardiac region
small, narrow, superior entryway into the stomach lumen from the esophagus
rungae
rings that allow the stomach to expand greatly when it fills and then return to its normal size
greater curvature
outside curve of stomach
lesser curvature
inner curve of stomach
